// the MountainBike subclass has
// one field
public int seatHeight;
// the MountainBike subclass has
// one constructor
public MountainBike(int startHeight, int startCadence,
[Code] ....
At first,
Java Code: public int seatHeight; mh_sh_highlight_all('java');
tells us that seatHeight is NOT a static field (because of the absence of static keyword).
Whereas in the constructor, the absence of dot notation (like something like this.seatHeight) in
Java Code: seatHeight = newValue; mh_sh_highlight_all('java');
shows that it IS a non-member/static variable.
The term "Local variable" is related to scope. That is a local variable is one which is defined in a certain block of code, and its scope is confined inside that block of code.And a "Member variable" is simple an instance variable.
I read in a discussion forum that when local variables are declared (example code below), their name reservation takes place in memory but they are not automatically initialized to anything. On the other hand, when member variables are declared, they are automatically initialized to null by default.
Java Code: public void myFunction () { int [] myInt; // A local, member variable (because "static" keyword is not there) declared } mh_sh_highlight_all('java');
So it seems that they are comparing local variables and member variables. While I think a member variable can also be be local in a block of code, isn't it?
public class StudentNumber { /* public StudentNumber(){ System.out.println("test"); } */ private char c='W'; public StudentNumber(float i){ System.out.println(i);
[Code] ....
Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - c has private access in extention.pkgsuper.StudentNumber at extention.pkgsuper.ExtentionSuper.main
I have a Tcr object as a member variable of the JFrame. But When ChangeListener swings into action, the variable inside it are all nulls. the TcrPanel is created before the ChangeListener is triggered.
I'm trying to acces my variable "cost" so when i press a button it prints the cost(for now) but the int value just prints 0
public class Holiday extends JFrame { private RoutinePanel routine; // A panel for routine charge checkboxes private JPanel HolidayPanel; // A panel for non-routine charges
why I cant access a variable from another class, in particular why in the main class cant i assign " quiz1 = getQuizOne();" ? It constantly giving me error.
Java Code:
import java.util.Scanner; public class Grade { private int quiz1, quiz2, midtermExam, finalExam = 0; public static void main(String[] args) { Student John = new Student(); John.StudentData();
I want to access variable of java file into jsp Page. So I tried to do this but it does not work.
Problem : when I am trying to access "getName" method of java class into jsp file it displaying error, i already imported "Ajaxmethod.java" file in to "success.jsp" I want to access "getName" method in to jsp file without creating object of class.
Ajaxmethod.java package a.b; public class Ajaxmethod implements Action{ public String name; public String getName() { return name; }
I've been trying to learn more about Big O Notation and I've gotten stuck on a few pieces of code. What is the computational complexity for the following pieces of code?
1:
for(int i = n; i > 0; i /= 2) { for(int j = 1; j < n; j *= 2) { for(int k = 0; k < n; k += 2) { // constant number of operations
[Code] .....
5 : Determine the average processing time of the recursive algorithm. (int n) spends one time unit to return a random integer value uniformly distributed in the range [0,n] whereas all other instructions spend a negligibly small time(e.g., T(0) = 0)
int myTest(int n) { if(n <= 0) return 0; else { int i = random(n - 1); return myTest(i) + myTest(n - 1 - i);
6 : Assume array a contains n values, the method randomValue takes a constant number c of computational steps to produce each output value, and that the method goodSort takes n log n computational steps to sort the array.
I've to create a program to get user input in scientific notation. Now i'm confused that how can i check that how user have used the scientific notation. For example there are many ways to write a number in scientific notation. Also a user can either write a number as:
6.7E2 OR 6.7*10^2
How to handle this input and further convert it to double?
So recently I began Data Structures as core subject and the tutorials in this forum are great.
Right now, I seem to have trouble with Big Oh Notation algorithm and what is the mathematical side to it. "f(n) <= c.g(n), for n>=0.
The question I am working on is: Suppose we are maintaining a collection C of elements such that, each time we add a new element to the collection, we copy the contents of C into a new array list of just the right size. What is the running time of adding n elements to an initially empty collection C in this case?
i have two classes in two different files.i have this class:
Java Code:
public class Color { private int red; private int green; private int blue;
public Color(){ red = 0; green = 0; blue = 0; } mh_sh_highlight_all('java');
And i have this class :
Java Code:
public class Light { private Color color1; private boolean switchedon;
public Light(int red, int green, int blue){ //dont know what to write here . how can i use the members of the Color class here ? without using extends. } } mh_sh_highlight_all('java');
My question is to evaluate a Postfix notation entered from keyboard. I have no errors in my code but it prints only :
Exception in thread "main"
java.util.NoSuchElementException at ArrayStack.pop(PostFixEvaluation.java:72) at PostFixEvaluation.evaluatePostfix(PostFixEvaluatio n.java:107) at PostFixEvaluation.main(PostFixEvaluation.java:140)
I tried many values but it prints the same exception all the time.
I can understand basic concepts such as OOP, Threads, Events and GUI, I've coded a little but I've always had this bothering me:
Explaining by example:
public class X{ int x; String y; public static void main(String[] args){ x = 10; y = "hello ";
[Code] ....
Okay, i'm pretty certain that code won't work, but I just want to show you conceptually, not actually care whether the code works or not. In case I wanted to get that code to work I should have probably used a Swing application to get a KeyListener in the first place, but I guess I know that, and if this was working, what would happen theoretically is, the code would run, initialize x to 10, and y to hello, then when a key is pressed, it will update x to 11 and y to hello world, I'm pretty sure that's what happens.
In this case, I used a inner class to update it's parent's members, I've seen this done before and I can vouch for the fact that it's a legitimate way to code a class.
Now in this example:
class X{ int x; String y; public int getX(){ return x; } public String getY(){ return y; }
[Code] ....
So in this overly complicated example, i'm trying to share class X with both class Y and class Z, just that how to share the members of class X with the different classes without making a new instance of X. In the previous example, I could access the parent's members because the inner class was implicitly capable of accessing the parent's members. However in this case, If "Y" starts an instance of X, then how do I access it? because it's a side by side class not a hierarchy for me to access the parent's members.
So I am supposed to be changing infix notation to postfix notation using stacks. This is simply taking a string "3 + 5 * 6" (infix) and turning it into (3 5 6 * +" (postfix).
To do this, we are to scan the string from left to right and when we encounter a number, we just add it to the final string, but when we encounter an operand, we throw it on the stack. Then if the next operand has a higher input precedence than the stack precedence of the operator on the top of the stack, we add that operator to the stack too, otherwise we pop from the stack THEN add the new operator.
I am supposed to be utilizing a hash map but I don't see how you would go about doing this. We are supposed to store operators on the hash map but operators need their own character, input precedence, stack precedence, and rank. How do you use a hash map when you need to tie a character to 3 values instead of just 1? I just don't get it.
The following is our Operator class that we are to use. Another problem is this isn't really supposed to be modified, yet we were given two important variables (inputPrecedence and outputPrecedence) that we can't have nothing to be initialized to and no way of accessing? So that might be where a hash map comes in but I am not sure. I am not very sure on how they exactly work anyway...
public class Operator implements Comparable<Operator> { public char operator; // operator privateint inputPrecedence; // input precedence of operator in the range [0, 5] privateint stackPrecedence; // stack precedence of operator in the range [-1, 3]
[Code] ....
So my question mostly revolves around how I tie an Operator character to its required values, so I can use it in my code to test two operators precedence values.
My original thought was turn string into character array, but then I would need nested for/while loops to check if it is a number or letter, or if it is an operator and thus result in O(n^2) time
I've tried a couple ways to do it, and they don't work. I'm aiming for functionality like I got with the regular for loop, but from an enhanced for loop. Is this simply beyond the scope of an enhanced for loop, or am I just not getting the right syntax?
TestObject to1 = new TestObject("first", 11); TestObject to2 = new TestObject("second", 12); TestObject to3 = new TestObject("third", 13); TestObject to4 = new TestObject("fourth", 14); TestObject to5 = new TestObject(); List<TestObject> testList; testList = new ArrayList<TestObject>();
[code]....
The TestObject class is simply an int and a String, with getters getInt and getString. It all works fine with the regular for loop.
edit: I should probably mention that I know what I have in the enhanced for loop now will only display the class name and the hash. I've tried adding the .getString and .getInt, and tried a few other ways to make it work. I just reverted to this because it compiles and runs
Okay, I am supposed to implement the functionalities of the Set class using a private data member of type ListReferencedBased<E>,how the ListReferenceBased works with what I am trying to accomplish.I am trying to complete Set.java, and I have barely started and much of the code doesn't work. ListReferenceBased was given to me completed.
import java.util.Iterator; pubic class ListReferenceBased<E> implements ListInterface<E>, Iterable<E>{ /** reference to the first element of the list */ private Node<E> head; /** number of items in list */ private int numItems;
Got a problem with generics, which I'm still pretty new at. Here's a program that compiles fine:
import java.util.ArrayList; import javax.swing.JComponent; public class Experiments { public static void main(String[] args) { ListHolder holder = new ListHolder();
[Code] ....
It's useless, but it compiles. If I change Line 14, however, to add a generic type parameter to the ListHolder class, Line 10 no longer compiles:
import java.util.ArrayList; import javax.swing.JComponent; public class Experiments { public static void main(String[] args) { ListHolder holder = new ListHolder();
[Code] ....
I get this error:
Uncompilable source code - incompatible types: java.lang.Object cannot be converted to javax.swing.JComponent at experiments.Experiments.main(Experiments.java:10)
Apparently, the introduction of the type parameter leaves the compiler thinking that aList is of type Object. I can cast it, like this:
JComponent c = ((ArrayList<JComponent>)holder.aList).iterator().next();
That makes the compiler happy, but why is it necessary? How does adding the (unused) type parameter to the ListHolder class end up making the compiler think the aList member of an instance of ListHolder is of type Object?
when we create another variable and set it equal to the first : Car c2 = c1;
we're pointing c2 at the same car object that c1 points to (as opposed to pointing c2 at c1, which in turn points at the car). So if we have code like,
Car c1 = new Car(); Car[] cA = {c1, c1, c1, c1};
are we doing the same? Are we creating four *new* reference variables, each of which points at the same car (again as opposed to pointing them at c1 itself)? I think so, but want to make sure I'm understanding this correctly.
